The invention refers to a tight bearing suitable for particularly heavy duty conditions.
The bearings appointed to heavy duty operations are those as an example, assembled on the rotating parts of earthworks machines.
In these applications some elements like sand, stones, pebble gravel, mud, vegetable fibers, are very hard on the resistance and tightness of the bearing during all its operating life. At present, the bearings appointed to particularly heavy duty conditions are generally of the type having a multi-contact rubber seal, that is consisting of a central body restrained to the plate that acts as a screen, from which several abreast lips extend and form a seal on the rotating element. Alternatively, several abreast rubber rings are assembled in the respective housings of the screen-plate instead of a central rubber body.
These devices having several sealing lips have the purpose of creating barriers to stop the entrance of external agents into the body of the bearing.
Obviously, the more are the contact surfaces (lips) on the rotating part, the higher is the friction produced by the bearing: consequently, a reduction of the rotation speed takes places and/or a shorter life of the bearing.
Furthermore, the above solutions require a high precision of the parts assembly, and this may be difficult to realize; a violent crash of the element on which the bearing is assembled or a strong hit against a stone is sufficient to cancel the optimum assembly conditions and consequently a quick wear of the bearing takes place.
In order to remove the above mentioned troubles, the present invention proposes to provide a bearing supplied with an axial rubber lip applied on a protection plate assembled on the rotating part and sliding on a conical surface of the plate of the immovable part of the bearing.
This solution allows a sensible reduction of the friction as it is less responsive to axial variations both during assembly and if crashes occur. The possibility to operate at higher speed and lower operative temperature derives from the above statement and the result is a longer operating life of the bearing.